System and Method for Controlling a Stand-Alone Direct Current Power System

ABSTRACT

Various implementations described herein are directed to systems, apparatuses and methods for operating stand-alone power systems. The systems may include power generators (e.g., photovoltaic generators and/or wind turbines), storage devices (e.g., batteries and/or flywheels), power modules (e.g., power converters) and loads. The methods may include various methods for monitoring, determining, controlling and/or predicting system power generation, system power storage and system power consumption.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/818,004, filed Mar. 13, 2020, which is a continuation of U.S.application Ser. No. 15/861,748, filed Jan. 4, 2018, now U.S. Pat. No.10,628,897, which claims priority to U.S. provisional application Ser.No. 62/444,494, filed Jan. 10, 2017. The entire contents of theaforementioned applications are incorporated herein by reference.

BACKGROUND

A stand-alone power system (SAPS), also known as remote area powersupply (RAPS), may be an off-the-grid electricity system that may besuitable for locations that are not fitted with an electricitydistribution system. Typical SAPS may include one or more methods ofelectricity generation, energy storage, and regulation. Storage may beimplemented as a battery bank, but other solutions exist including fuelcells and super capacitors, for example. Power drawn directly from thestorage may be used for lighting as well as for other direct current(DC) appliances. Stand-alone photovoltaic power systems may beindependent of the utility grid and may use solar panels only or may beused in conjunction with a diesel generator, a wind turbine orbatteries, for example. Challenges for the design and implementation ofstand-alone power systems may include improving their performance,establishing techniques for accurately predicting their output, andreliably integrating them with other generating sources.

SUMMARY

The following summary is a short summary of some of the inventiveconcepts for illustrative purposes only, and is not intended to limit orconstrain the inventions and examples in the detailed description. Oneskilled in the art will recognize other novel combinations and featuresfrom the detailed description.

Illustrative embodiments disclosed herein may include a direct current(DC) system utilized to supply DC power to a load and/or a storagedevice. The DC system may include various interconnections of groups ofDC power sources that also may be connected in various series, parallel,series parallel, and/or parallel series combinations, for example.

As noted above, this Summary is merely a summary of some of the featuresdescribed herein. It is not exhaustive, and it is not to be a limitationon the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood with regard to the followingdescription, claims, and drawings. The present disclosure is illustratedby way of example, and not limited by, the accompanying figures.

FIG. 1A illustrates a power system, according to a feature of one ormore illustrative embodiments.

FIG. 1B illustrates a power system, according to a feature of one ormore illustrative embodiments.

FIG. 1C shows further details of a power module, according to a featureof one or more illustrative embodiments.

FIG. 1D shows further details of a power circuit, according to a featureof one or more illustrative embodiments.

FIG. 1E shows a buck+boost circuit implementation for a power circuit,according to a feature of one or more illustrative embodiments.

FIGS. 1F, 1G and 1H show connection configurations, according tofeatures of one or more illustrative embodiments.

FIG. 1I shows a connection configuration in a power system, according toa feature of one or more illustrative embodiments.

FIG. 1J shows a power system operably connected to a central controller,according to a feature of one or more illustrative embodiments.

FIG. 1K illustrates a power system, according to a feature of one ormore illustrative embodiments.

FIGS. 2A and 2B show views of a storage device, according to a featureof one or more illustrative embodiments.

FIGS. 2C, 2D and 2E are flow charts describing methods for operating apower system according to one or more illustrative embodiments.

FIGS. 3A and 3B show power systems, according to a feature of one ormore illustrative embodiments.

FIG. 4A is a block diagram of a power system according to one or moreillustrative embodiments.

FIG. 4B is a flow chart describing a method for operating a power systemaccording to one or more illustrative embodiments.

FIG. 5 shows a user interface according to a feature of one or moreillustrative embodiments.

DETAILED DESCRIPTION

In the following description of various illustrative embodiments,reference is made to the accompanying drawings, which form a parthereof, and in which is shown, by way of illustration, variousembodiments in which aspects of the disclosure may be practiced. It isto be understood that other embodiments may be utilized and structuraland functional modifications may be made, without departing from thescope of the present disclosure.

Reference is made to FIG. 1A, which shows a block diagram of a powersystem 100, according one or more illustrative embodiments. A connectionconfiguration 111 includes a power source 101 with direct current (DC)output terminals connected to the input terminals of power module 103.DC output terminals of power module 103 may include a positive DC outputconnected to a positive DC input terminal of load 109 and a positive DCinput terminal of storage device 107. Power module 103 may furtherinclude a negative DC output terminal that may be connected to anegative DC input terminal of load 109 and a negative DC input terminalof storage device 107. In the descriptions that follow, power source 101may be a photovoltaic (PV) generator, for example, a PV cell, a seriesstring of PV cells, a parallel connection of serially connected PVstrings of PV cells, a photovoltaic or solar panel, a DC generator, abattery, or a fuel cell. Storage device 107 may be variouslyimplemented, for example, using a battery, super capacitor, flywheeland/or UltraBattery™. Load 109 may comprise one or more DC loadcircuits. For example, load 109 may comprise communication equipment(e.g. a cellular base-station) or other devices deployed in a locationthat might not be connected to an electrical grid. Power module 103 maybe configured to output a DC voltage suitable for powering load 109, forexample, 48V.

Reference is made to FIG. 1B, which shows a block diagram of a powersystem 100 a, according one or more illustrative embodiments. Aconnection configuration 111 a includes a power source 101 with directcurrent (DC) output terminals connected to the input terminals of powermodule 103P. DC output terminals of power module 103P may include afirst positive DC output connected to a positive DC input terminal ofload 109, and a second positive DC output connected to a positive DCinput terminal of storage device 107. As described later in thedescriptions that follow, the first and second positive DC outputs ofpower module 103P may be utilized so that power from power module 103Pmay be supplied to load 109, or to load 109 and storage device 107.Power module 103 may further include a negative DC output terminal thatmay be commonly connected to the negative DC input terminals of load 109and storage device 107.

Power source 101 shown in both FIGS. 1A and 1B may be, for example, awind turbine that produces alternating current (AC) and power modules103 and 130P may serve as AC-to-DC converters such as rectifiers and/orinclude use of switched mode power supply, for example.

Reference is now made to FIG. 1C, which illustrates circuitry that maybe found in a power device such as power module 103, according to anillustrative embodiment. Power module 103 may be similar to or the sameas power module 103P shown in FIG. 1B or other power modules asdescribed in the descriptions that follow. In some embodiments, powermodule 103 may include power circuit 135. Power circuit 135 may includea direct current to direct current (DC/DC) converter such as a Buck,Boost, Buck/Boost, Buck+Boost, Cuk, Flyback and/or forward converter. Insome embodiments, power circuit 135 may include a directcurrent-alternating current (DC/AC) converter (also known as aninverter), such as a micro-inverter. Power circuit 135 may have twoinput terminals and two output terminals, which may be the same as theinput terminals and output terminals of power module 103. In someembodiments, power module 103 may include Maximum Power Point Tracking(MPPT) circuit 138, which is configured to extract increased power froma power source the power device is coupled to. In some embodiments,power circuit 135 may include MPPT functionality. In some embodiments,MPPT circuit 138 may implement impedance matching algorithms to extractincreased power from a power source the power device is coupled to.Power module 103 may further include controller 105 such as amicroprocessor, Digital Signal Processor (DSP), Application-SpecificIntegrated Circuit (ASIC) and/or a Field Programmable Gate Array (FPGA).Referring still to FIG. 1C, controller 105 may control and/orcommunicate with other elements of power module 103 over common bus 190.In some embodiments, power module 103 may include circuitry and/orsensor unit 125 configured to measure parameters directly or receivemeasured parameters from connected sensors and/or sensor interfacesconfigured to measure parameters on or near the power source, such asthe voltage and/or current output by the power source and/or the poweroutput by the power source. In some embodiments, the power source may bea photovoltaic (PV) generator comprising PV cells, and a sensor unit(e.g., one or more sensors and/or sensor interfaces) may directlymeasure or receive measurements of the irradiance received by the PVcells, and/or the temperature on or near the PV generator.

Referring still to FIG. 1C, in some embodiments, power module 103 mayinclude communication interface 129, which is configured to transmitand/or receive data and/or commands from other devices. Communicationinterface 129 may communicate using Power Line Communication (PLC)technology, or wireless technologies such as ZigBee™, Wi-Fi, cellularcommunication or other wireless methods. In some embodiments, powermodule 103 may include memory device 123, for logging measurements takenby sensor(s)/sensor interfaces 125 to store code, operational protocolsor other operating information. Memory device 123 may be Flash,Electrically Erasable Programmable Read-Only Memory (EEPROM), RandomAccess Memory (RAM), Solid State Devices (SSD) or other types ofappropriate memory devices.

Referring still to FIG. 1C, in some embodiments, power module 103 mayinclude safety devices 160 (e.g. fuses, circuit breakers and ResidualCurrent Detectors). Safety devices 160 may be passive or active. Forexample, safety devices 160 may include one or more passive fusesdisposed within power module 103 and designed to melt when a certainamount of current flows through it, disconnecting part of power module103 to avoid damage. In some embodiments, safety devices 160 may includeactive disconnect switches, which are configured to receive commandsfrom a controller (e.g. controller 105, or an external controller) todisconnect portions of power module 103, or configured to disconnectportions of power module 103 in response to a measurement measured by asensor (e.g. a measurement measured or obtained by sensor unit 125). Insome embodiments, power module 103 may include auxiliary power circuit162, which is configured to receive power from a power source coupled topower module 103, and output power suitable for operating othercircuitry components (e.g., controller 105, communication interface 129,etc.). Communication, electrical coupling and/or data-sharing betweenthe various components of power module 103 may be carried out overcommon bus 190.

Referring still to FIG. 1C, in some embodiments, power module 103 mayinclude transistor Q9 coupled between the inputs of power circuit 135.Transistor Q9 may be controlled by controller 105. If an unsafecondition is detected, controller 105 may set transistor Q9 to ON,short-circuiting the input to power circuit 135. Transistor Q9 may becontrolled in conjunction with switch SW1 of FIG. 1D. When switch SW1and transistor Q9 are OFF, each pair of power sources 101 of FIGS. 1Aand 1B are disconnected. In a case in which the pair of power sources101 are photovoltaic (PV) generators, each PV generator provides anopen-circuit voltage at its output terminals. When switch SW1 andtransistor Q9 are ON, each pair of PV generators of FIGS. 1A and 1B areconnected and short-circuited, the pair of PV generators providing avoltage of about zero to power circuit 135. In both scenarios, a safevoltage may be maintained, and the two scenarios may be staggered toalternate between open-circuiting and short-circuiting PV generators.This mode of operation may allow continuous power supply to systemcontrol devices, as well as provide backup mechanisms for maintaining asafe voltage (i.e., in case a switch SW1 malfunctions, operation oftransistor Q9 may allow continued safe operating conditions).

Reference is made to FIG. 1D, which shows further details of powercircuit 120 utilized in power module 103P, according to one or moreillustrative embodiments. Controller 105, memory device 123 andcommunication interface 129 are not included in the drawing of the powermodules 103 and 103P in order to simplify the drawing. A negative outputterminal of power source 101 connects to a negative input terminal ofpower circuit 135. In some embodiments, a switch SW1 may be provided asan optional component that connects serially between a positive outputterminal of power source 101 and a positive input terminal of powercircuit 135 for purposes of safety in order to isolate power source 101from the positive input terminal of power circuit 135. In someembodiments, switch SW1 may connect in parallel across power source 101,so that in the case of power source 101 being a solar panel which isunderperforming compared to other solar panels, the solar panel may bebypassed when switch SW1 is ON.

A positive output terminal of power circuit 135 may be split in two andmay connect respectively to a positive input terminal of load 109 and apositive input terminal of storage device 107. A switch SW2 may beprovided as an optional component, which connects serially between thepositive output terminal of power circuit 135 and a positive inputterminal of storage device 107. With switch SW2 in an ON position, load109 and storage device 107 are connected in parallel across outputterminals of power circuit 135. With switch SW2 in an OFF position, load109 remains connected across the output terminals of power circuit 135,and storage device 107 is disconnected from the output terminals ofpower circuit 135. In the context of a photovoltaic (PV) panelimplementation of power system 100, operation of SW2 when ON may allowpower (e.g. power of FIG. 2C) to be supplied to load 109 and storagedevice 107 during operation when power from power source 101 may besufficient (e.g. during the daytime). Switch SW2 when OFF may allowpower to be supplied to load 109 if charging of storage device 107 is tobe avoided (e.g., when storage device 107 is already substantially fullycharged, or to reduce charging cycles of storage device 107, or whenpower from power source 101 is insufficient to both power load 109 andstorage device 107). When power from the power source 101 may beinsufficient, switch SW2 may be in the ON position, allowing power fromstorage device 107 to be applied to load 109.

Sensor/sensor interface 125 operatively attached to controller 105 mayinclude analog to digital converters (not shown) that may be connectedto sensors 125 a, 125 b and 125 c. Sensors 125 a, 125 b and 125 c may beconfigured to sense electrical parameters such as current, voltageand/or power of load 109, storage device 107 and the input and/or outputparameters of power circuit 135 and power source 101. Optionally,sensor/sensor interface 125 b may also include an energy gauge to countcoulombs (amperes per second) when either charging or dischargingstorage device 107. Sensors 125 a, 125 b and 125 c may optionally belocated and integrated inside power circuit 135. Sensors 125 b and 125 cmay be optionally spatially located in the vicinity of storage device107 and load 109 respectively. Similarly, sensor 125 a may be spatiallylocated in the vicinity of power source 101. Additional sensors may beadded and configured to sense, for example, temperature, humidity andluminance.

Operation of switch SW1 may be based on electrical parameters sensed inpower circuit 120 and may be activated in any case of over-voltage orover-current, over-temperature and under-voltage or under-current.

Reference is made to FIG. 1E, which shows a buck+boost circuitimplementation for power circuit 135, according to a feature of one ormore illustrative embodiments. Capacitor C1 may connect in parallelacross the positive and negative input terminals of the buck+boostcircuit where the voltage is indicated as VIN. Capacitor C2 may connectin parallel across the positive and negative output terminals of thebuck+boost circuit where the voltage is indicated as VOUT. The sourcesof insulated gate field effect transistors (IGFETs) S3 and S2 connect tothe common negative output and input terminals of the buck+boostcircuit. The drain of switch S1 connects to the positive input terminal,and the source of switch S1 connects to the drain of switch S3. Thedrain of switch S4 connects to the positive output terminal, and thesource of switch S4 connects to the drain of switch S2. Inductor Liconnects respectively between the drains of switches S3 and S4. Thegates of switches S1, S2, S3 and S4 may be operatively connected tocontroller 105 (see also FIG. 1C).

Switches S1, S2, S3 and S4 may be alternatively implemented for exampleusing metal oxide semiconductor field effect transistors (MOSFETs),insulated gate bipolar transistors (IGBTs), bipolar junction transistors(BJTs), Darlington transistor, diode, silicon controlled rectifier(SCR), Diac, Triac or other semi-conductor switches. Similarly,implementation for power circuit 135 may include, for example, a buckcircuit, a boost circuit, a buck/boost circuit, a Flyback circuit, aForward circuit, a charge pump, a Cuk converter or any other circuitthat may be utilized to convert power on the input of power circuit 135to the output of power circuit 135.

Power circuit 135 may include or be operatively attached to a maximumpower point tracking (MPPT) circuit 138. MPPT circuit 138 may also beoperatively connected to controller 105 or another controller. MPPTcircuit 138 under control of controller 105 or a central controller maybe utilized to increase power extraction from power sources 101 and/orto control voltage and/or current supplied to load 109 and storagedevice 107 in order to avoid damage to load 109 and storage device 107.Control of voltage and/or current to load 109 and storage device 107therefore, might not necessarily utilize the feature of increasing powerfrom power sources 101, but rather may utilize MPPT circuit 138 tooperate at a point in order to shed some of the power produced by powersources 101.

Reference is now made to FIG. 1F, which shows a block diagram of a powersystem 100 b, according to one or more illustrative embodiments.Connection configuration 111 a shows a power source 101 with directcurrent (DC) output terminals connected to input terminals of powermodule 103. Connection configuration 111 b shows two power sources 101connected in a series connection, with direct current (DC) outputterminals of the series connection connected to the input terminals ofpower module 103. A negative output terminal of power module 103 inconnection configuration 111 a may be connected in common with thenegative input terminals of load 109 and storage device 107. Thepositive output terminal of power module 103 in connection configuration111 a may be connected to the negative output terminal of another powermodule 103 or to power module 103P in connection configuration 111 b.The positive output terminal of power module 103P may connect to thepositive input terminal of load 109. A positive output terminal of powermodule 103P that is coupled to switch SW2 may connect to the positiveinput terminal of storage device 107. In the descriptions that follow,connections to storage device 107 and/or load 109 may be from powermodule 103P or power module 103.

Series connections of power sources 101 as shown in connectionconfiguration 111 b may provide a higher voltage input into power module103 compared to an input to power module 103 from a single power source101. Series connections of the outputs of power modules 103 maysimilarly provide a higher voltage output into load 109 and/or storagedevice 107.

Reference is now made to FIG. 1G, which shows a block diagram of a powersystem 100 c and connection configurations 111 c and 111 d, according toone or more illustrative embodiments. The series output connections ofpower modules 103 and 103P shown in FIG. 1F to load 109 and storagedevice 107 may be the same as the series output connections of powermodules 103 and 103P shown in FIG. 1G. Connection configuration 111 dmay have multiple power sources 101 a with their output terminalsconnected in parallel across the input of power module 103. Powersources 101 a may differ in power rating output (Power=Voltage xCurrent) compared to the power rating output of power sources 101 shownwith outputs connected in a series connection which may be connectedacross the input of power module 103P.

Reference is now made to FIG. 1H, which shows a block diagram of a powersystem 100 d and a connection configuration 111 d, according to one ormore illustrative embodiments. Again, the series connection of theoutputs of power modules 103 and 103P may be the same as shown in FIG.1F and FIG. 1G. The alternative connection configuration is shown withmultiple connection configurations 111 d where each connectionconfiguration 111 d has multiple power sources 101 with their outputterminals connected in parallel across the input of respective powermodules 103/103P.

Reference is now made to FIG. 1I, which shows a connection configuration111 in power system 100 e, according to one or more illustrativeembodiments. Connection configurations 111 and 111P have their outputsconnected in a parallel connection that may be connected to the inputterminals of the load 109 and storage device 107 via connectionconfiguration 111P. In particular, connection configuration 111Pincludes the use of power module 103P to provide two DC positiveconnections to load 109 and storage device 107 via switch SW2 (see alsoFIG. 1D). In another implementation, connection configurations 111 maybe used to provide a single DC connection to load 109 and storage device107. In general, any number of connection combinations of multipleconnection configurations 111 may include DC power sources of differingtypes so that one connection configuration 111 has photovoltaic panelsfor example, while another connection configuration 111 has wind poweredDC generators. In sum, connection configurations 111 may also includehybrid combinations of DC power derived from the interconnection ofbatteries, wind powered DC generators and/or petrol generators forexample.

In the various aspects described above for power systems 100 a, 100 b,100 c, 100 d and 100 e, a communication protocol used by communicationinterface 129 of FIG. 1C in one primary power module 103P maycommunicatively control one or more other power modules 103 which areknown as secondary power modules 103. Once a primary/secondaryrelationship is established, a direction of control may be from theprimary power module 103P to the secondary power modules 103. When oneprimary power module 103P experiences a reduction of power input (e.g.due to shading in the case of photovoltaic panels used for power sources101), and the outputs of power modules 103 are connected in series, thepower supply to power the primary module 130P may be taken from theother power module 103 outputs (e.g. by coupling auxiliary power circuit162 to an output of power circuit 135, which may be coupled toconductors carrying power from other power modules 103). In the case ofshading of a panel in a series string including power modules 103 and/orpower module 103P, a current bypass may be applied to the respectivepower module 103/103P and panel.

A communication protocol may be implemented for the direction of controlbetween power modules and/or for transferring data and/or or commandsfrom power module 103P to and between power modules 103 using, forexample power line communication (PLC) techniques over power lines ofpower system 100, near field communication (NFC), Wi-Fi™ to connect to awireless local area network (WLAN), Bluetooth™, ZigBee™ WiMAX™controller area network (CAN) bus, local interconnect network (LIN), orany other suitable communication protocol.

Reference is now made to FIG. 1J, which shows connection of power system100 f operably connected to central controller 185, according to one ormore illustrative embodiments. Central controller 185 may, in a similarmanner to power modules 103/103P, include a controller 105 coupled to amemory device 123 and a communication interface 129. Central controller185 may receive its power supply in order to operate from power modules103/103P, from an additional auxiliary power supply or from storagedevice 107. Central controller 185 may receive from each power module103/103P the electrical parameters sensed by sensors 125 a, 125 b and125 c such as current, voltage and/or power of load 109, storage device107 and/or the input and/or output of power circuit and power source101. In response to the sensed electrical parameters of each powermodule 103/103P, central controller 185 may send appropriate controlsignals to each power module 103/103P of power system 100 b.

In the descriptions above concerning power modules 103P/103 and indescriptions of other power modules that follow, each power moduleutilized in power systems described herein may have the option of beingdesignated as a primary power module, whereas other power modules may bedesignated as secondary power modules. A power module designated as aprimary power module may be determined based on by a decision algorithmrunning in central controller 185 and/or by a remote computing platformoperatively attached to central controller 185. In some embodiments,multiple power models may run a decision algorithm to select one of themultiple power models as a primary power module. Power modules 103P/103,central controller 185 and in descriptions of other power modules thatfollow, may derive their power needed to operate on the output side ofthe power modules, from storage device 107 and/or auxiliary powercircuits 162. Auxiliary power circuits 162 may similarly derive theirpower needed to operate on the output side of the power modules or froma storage device 107.

Reference is now made to FIG. 1K, which shows a power system 100 g,according to one or more illustrative embodiments. Power sources 101 areshown with their outputs connected in a parallel connection. Theparallel connection may be connected across the input of protectiondevice PD1, which may be connected to the input of storage device 107.The parallel connection may also be connected across the input of powermodule 103 a, and the output of power module 103 a may be connectedacross load 109. Alternatively, the outputs of power sources 101 mayhave their outputs connected in a series connection that may also besimilarly connected across the inputs of the input of power module 103 aand protection device PD1. Indeed, any number of series/parallel orparallel series connections of power sources 101 may be connected acrossthe inputs of power module 103 a and protection device PD1.

Fuse F1 may connect between the positive terminal of storage device 107and protection device PD1. Fuse F1 may be an integrated part ofprotection device PD1 or an integrated part of storage device 107. FuseF2 may connect to the positive terminal of the parallel connection andto the positive input terminal of power module 103 a. Fuse F2 may be anintegrated part of protection device PD1. In some embodiments,protection device PD1 may be an integrated part of storage device 107.

Load 109 may include power module 103 a as an integrated part of load109 and/or may also include protection device PD1. In a similar way,storage device 107 may also have a power module and a protection deviceattached or the power module, and/or the protection device PD1 may be anintegrated part of storage device 107.

Protection device PD1 is shown implemented with a Zener diode ZD1.Protection device PD1 in conjunction with fuses F1 and F2 that may beutilized for over-current and/or over-voltage protection and/or reversepolarity protection when power is being supplied to or from storagedevice 107. For example, Zener diode ZD1 may be rated to protect storagedevice 107 from an over-voltage condition, and fuses F1 and/or F2 may berated to protect storage device 107 from an over-current condition.Protection device PD1 may also implemented with other protection devicessuch as circuit breakers and/or residual current devices.

Reference is now made to FIGS. 2A and 2B, which show respective views ofstorage device 107, according to one or more illustrative embodiments.FIG. 2A shows storage device 107 after it has been mostly depleted butnot empty of charge. The state of charge (SOC) of storage device 107 isshown by an area of cross hatching which is below a lower level ofpercentage charge L %. Central controller 185 may monitor and controlthe discharge of storage device 107 to prevent storage device 107 fromfalling below a minimal level ML %.

FIG. 2B shows storage device 107 after it has been charged and/orpartially depleted. The state of charge (SOC) of storage device 107 isshown by an area cross hatching which is above a higher level ofpercentage charge H %. Central controller 185 may be configured tomonitor and control the charge and/or discharge of storage device 107 sothat storage device 107 is not damaged by overcharging or fromover-depletion.

When storage device 107 is a battery, central controller 185 may haveaccess to a charge profile stored in memory device 123 for the battery.For example, when using a lead acid battery for storage device 107, acharge profile for optimal charging of the lead acid battery mayindicate preferred use of a constant voltage level for at least aminimum period of time. Measuring and controlling the temperature of thelead acid battery may also improve the performance and/or reliability ofthe battery, since the lead acid battery may need to stay cool whenbeing charged so as to ensure optimal charging. In contrast to the leadacid based battery, a nickel based battery may prefer a fast charge ratewith constant current. Consideration may be given to different types ofbatteries when charging and discharging to ensure that correct voltages,currents, temperatures and appropriate time periods of charge anddischarge are monitored, controlled and applied to batteries so as toavoid damage.

Central controller 185 may be utilized to include control parameters forpower modules 103/103P to function as constant current and/or constantvoltage sources when storage device 107 is being charged according to anappropriate charge profile. The appropriate charge profile may considerthe temperature of the battery, for example. The appropriate chargeprofile may further provide data logging via communication interface 129to a server of the transfer of charge and/or discharge of a battery inorder to access the ageing and use of batteries. Such data logging maythen be able to provide an estimate of projected battery life and timingof battery replacement for example.

Reference is now made to FIG. 2C, which shows as a flow chart a method201 according to one or more illustrative embodiments. Method 201 may beutilized for power systems 100 a-d described above. In the followingdescription of method 201, reference to the use of central controller185 is made, however, the following description may also use one primarypower module 103P to control one or more other secondary power modules103.

Method 201 may begin in a start mode at step 210, at a time when powersources 101 may be producing substantially no power (e.g. at nighttime). If power from power sources 101 is substantially zero, powersupplied to load 109 may come from storage device 107. A feature ofstart mode in step 210 may be the monitoring of sensor units 125, 125 a,125 b and 125 c to see if power sources 101 have begun to produce powerand to monitor the state of charge (SOC) of storage device 107.Generally, in start mode in step 210, storage device 107 may supply load109 with DC power.

When power sources 101 begin to produce power (e.g., in the case wherephotovoltaic generators are used as power sources 101, at dawn), centralcontroller 185 may receive a signal from power modules 103/103P toindicate that the power sources 101 have started to produce power. Powerproduced by power sources 101 may be measured in step 200 using sensors125 and in decision step 202, if power from power sources 101 is notsufficient (e.g., the power is below a threshold), a power system 100a-d may remain in start mode status (step 210). In general, fordescriptions that follow a threshold may be predetermined and/ordynamically determined. In decision step 202, if the amount of powerfrom power sources 101 is above a minimum threshold level of power so asto power load 109 or storage device 107 effectively, then the state ofcharge (SOC) of storage device 107 may be obtained (step 204) usingsensors 125/125 b.

At decision step 208, power and SOC may be used to determine how tosupply load 109 with power. However, if at any point in time the powerfrom power sources 101 falls below a threshold, power system 100 mayreturn to start mode status (step 210). Power from power sources 101 notbeing sufficient may occur when, for example, PV generators are shadedor at dusk or during the night. Where power sources 101 may be windpowered DC generators for example, start mode in step 210 may be enteredinto due to the absence of substantial wind.

In general, for discussions that follow, features of decision step 208are shown in greater detail with reference to PV power sources. Powersupplied to load 109 depends on the amount of power measured in step 200and the state of charge of storage device 107.

Reference is now made to FIG. 2D, which shows further details ofdecision step 208 shown in FIG. 2C, according to one or moreillustrative embodiments. Decision step 208 may be reached when theamount of power from power sources 101 is above a minimum thresholdlevel of power to supply load 109. Power of power sources 101 may bemeasured at step 200 and the state of charge (SOC) of storage device 107may be obtained at step 204 using sensor units 125, 125 a, 125 b and 125c. Decision step 214 may be based in part on the SOC of storage device107. When in start mode at step 210, storage device 107 might not havebeen depleted so much that the level of charge may still be abovepercentage charge level H % and/or somewhere in between percentagecharge level H % and percentage charge level L %. As such, when theamount of power available from power sources 101 is above a minimumthreshold level of power, storage device 107 along with the power frompower sources 101 may be utilized to supply a supplemental power to load109 (step 216).

Power provided to load 109 from storage device 107 may extend theprovision of power to load 109 when power from power sources 101 isinsufficient. Furthermore, depletion of storage device 107 may allow indecision step 218 for charge of storage device 107 (step 220) later at amore opportune time when the power from power sources 101 may have anincreased power output. The opportune time when power from power sources101 have an increased power output may also coincide to include supplyof power to load 109 in step 222. The increased power may then be usedto storage device 107 with either constant current or constant voltage,for whichever of the two is more suitable for the type of storage device107.

At decision step 218, if storage device 107 does not need charging, thecontroller carrying out decision step 208 may return to decision step214 and consider depleting storage device 107. Depleting storage device107 may be useful, for example, for avoiding damage to batteries. Damageto batteries may be avoided for example, by charging when the SOC of thebattery is in the vicinity below percentage charge L % as opposed tocharging when the SOC is somewhere in between percentage charge H % andpercentage charge L %.

Reference is now made to FIG. 2E, which shows further details ofdecision step 208 shown in FIG. 2C, according to one or moreillustrative embodiments. Decision step 208 may be executed during adaytime operation mode when the amount of power from power sources 101is above a minimum threshold level of power, and power supply to load109 and/or storage device 107 may be from power sources 101 (step 222).At step 224, a signal may be sent to power modules 103/103P. Varioustypes of the signals may exist. The signal may be a signal sent to powermodules 103/103P to possibly serve the function of instructing the powermodules 103/103P to shut down completely, perhaps due to a safetycondition in power system 100, 100 a, 100 b, 100 c, 100 d and 100 e. Thesignal may be a signal sent to power modules 103/103P to possibly servethe function of instructing the power modules 103/103P to reduce power(e.g. by an explicit message or a lack of a signal) in order to shedpower. The signal may be a signal sent to power modules 103/103P topossibly serve the function of instructing the power modules 103/103P tolet the power modules 103/103P to continue to control power at thepresent level, or to increase power to load 109 and/or storage device107. A first signal sent to power modules 103 from central controller185 may cause no adjustment of the power conversion of modules 103/103Pfrom input to output of power modules 103/103P. A second signal maycause a percentage (%) change in the adjustment of the power conversionfrom input to output of modules 103/103P. Power output of power sources101 may be measured in step 200 from sensors 125 a, 125 b and 125 c inrespective power modules 103/103P.

At decision step 226, if power from power sources 101 is not sufficientto power load 109, which may be indicative of, e.g. dusk, nighttimeexcessive shading of PV generators or reduction of wind, power system100 a-d may return to start mode status (step 210 of FIG. 2C).

At decision step 228, if power from power sources 101 is sufficient topower load 109 then supply of power to load 109 may continue in step 222and the first signal may be sent to power modules 103/103P in step 224.

If at decision step 228, power from power sources 101 is more thansufficient to power load 109, then control of power to load 109 maycontinue in step 222 and a second signal may be sent to power modules103 in step 224. The second signal sent to power modules 103/103P instep 224 therefore, may allow reduction of power supplied to load 109 iftoo much power is available.

Supply of power to load 109 in steps 222 and/or 216, as part of decisionstep 208, may take into account a load profile stored in memory device123. A load profile may include an information update via communicationinterfaces 129 that may include local weather information such ascurrent and forecasted temperature, cloud cover and amount of sunlightfor example. The load profile may also include updated information withregards to an updatable load demand history of a power system 100 a-dwith reference to daily and nightly demand, weekday demand and monthlydemand for example.

Reference is now made to FIG. 3A, which shows a power system 100 h,according to one or more illustrative embodiments. Power system 100 hmay be similar to power system 100 b shown in FIG. 1J with an additionalpower module 103 a. A negative output terminal of power module 103 inconnection configuration 111 a may be connected in common with thenegative input terminals of load 109, storage device 107 and powermodule 103 a. A positive output terminal of power module 103 a mayconnect to a positive input terminal of load 109. A positive outputterminal of power module 103 in connection configuration 111 a may comefrom a positive output terminal of power circuit 135 or from thepositive output terminal of power circuit 135 through switch SW2. Apositive output terminal of power module 103P may connect to thepositive input terminal of power module 103 a. The positive outputterminal of power module 103 that is coupled to switch SW2 may connectto the positive input terminal of storage device 107. Voltage fromseries connected power modules 103/103P outputs is shown as Vstringwhich is the voltage applied to storage device 107 and the input ofpower module 103 a. Central controller 185 may be operatively attachedto power module 103 a and power modules 103/103P.

Reference is now made again to method 201 and in particular to furtherdetails of decision step 208 shown in FIG. 2E with respect to powersystem 100 h shown in FIG. 3A, according to one or more illustrativeembodiments. The description that follows may be suitable for operationwhen the amount of power produced by power sources 101 is above theminimum threshold level of power and power supply of power to load 109and/or storage device 107 (e.g., when power sources 101 are PVgenerators, during daytime operation).

In step 222 supply of power to load 109 may be via power module 103 a.Voltage Vstring, from series connected power modules 103/103P outputsmay be connected across the input of power module 103 a as previouslydescribed in FIG. 3A. Power module 103 a for example may be utilized ina situation where the voltage required by load 109 is less than voltageVstring. When different voltage supply values are desired for multipleloads 109, multiple power modules 103 a may be used for the multipleloads 109. For example, if a load 109 requires a 12-volt supply, powermodule 103 a may be configured and/or operated to provide the 12-voltsrequired by load 109. The 12-volts required by load 109 may be providedby use of power module 103 a to convert power (voltage [Vstring] xcurrent) provided from the series connected power modules 103 outputsconnected across the input of power module 103 a. In another example ofstep 222, if storage device 107 is a 48-volt lead acid battery, thenpower modules 103 may be configured and/or operated to supply a constantvoltage of 50 volts in order to charge the battery. Alternatively, ifstorage device 107 is a 48-volt nickel based battery, then power modules103 may be configured and/or operated to supply a constant current tocharge the battery. The provision of power module 103 a may enable theoption to provide appropriate power to storage device 107 and/or correctvoltage to loads 109 via power modules 103 a.

In step 224, the first and second signals and may be sent to powermodules 103/103 a. Power output of power sources 101 may be measured instep 200 using sensor units 125, 125 a, 125 b and 125 c. At decisionstep 226, if power from power sources 101 is not sufficient to powerload 109, which may be indicative of dusk, nighttime or excessiveshading of PV generators, power system 100 h may return to start modestatus (step 210).

At decision step 228 if power from power sources 101 is sufficient topower load 109 then supply of power to load 109 may continue in step 222and first signal may be sent to power modules 103/103 a in step 224. Amaximum power point tracking (MPPT) circuit 138 utilized in powermodules 103/103 a under control of controller 105 or central controller185 may be utilized to increase power extraction from power sources 101or to control voltage and/or current supplied to load 109 and storagedevice 107 to increase efficiency of or avoid damage to load 109 and/orstorage device 107. Control of voltage and/or current to load 109 andstorage device 107 therefore, may not necessarily utilize the feature ofincreasing power drawn from power sources 101 but rather may utilizeMPPT circuit 138 to be at a reduced power point in order to shed powerproduced by power sources 101. A second signal may be sent to powermodules 103/103 a in step 224 and may allow reduction of power suppliedto load 109 if too much power is available.

Reference is now made to FIG. 3B, which shows a power system 100 i,according to one or more illustrative embodiments. Power system 100 imay be similar to power system 100 k shown in FIG. 3A with additionalpower modules 103 b. Shown are multiple storage devices 107 with inputsconnected to respective power modules 103 b. Storage devices 107 may beall the same type or may include various different types of batteriesfor example. A feature of power modules 103 b according to certainaspect may be that power modules 103 b may convert powerbi-directionally. A first direction of power conversion by power module103 b may be when multiple storage devices 107 are sourced withconverted power from power modules 103/103P. Storage devices 107 mayreceive converted power from power modules 103/103P when storage devices107 are being charged, for example. A second direction of powerconversion may be when power from storage devices 107 is converted bypower module 103 b to be supplied to load 109 and/or power module 103 aconnected to load 109. Central controller 185 may be operativelyattached to power module 103 a and power modules 103 b. The signals sentto power modules 103 a/103 b may serve the function of instructing thepower modules 103 a/103 b to shut down completely, perhaps due to asafety condition in power systems 100 h and 100 i, to reduce power(e.g., an explicit message or lack of a signal) in order to shed power,to let the power modules 103 a/103 b to continue to control power at thepresent level or to increase power to load 109 and/or storage device 107respectively.

Reference is now made again to method 201 and in particular to furtherdetail of decision step 208 shown in FIG. 2D with respect to powersystem 100 i shown in FIG. 3B, according to one or more illustrativeembodiments. The description that follows may concern both the chargeand discharge of multiple storage devices 107 shown in FIG. 3B. Powersystem 100 i may include additional power modules 103 b connectedrespectively to the terminals of storage devices 107. As describedpreviously with regard to FIG. 3B, power modules 103 b may convert powerbi-directionally in order to charge or discharge storage devices 107.MPPT circuits 138 in power modules 103/103P may improve power transferto storage devices 107 and/or load 109. By way of example in thedescription which follows, in order to simplify the description, two ofthe same type of storage devices 107 are used with respective powermodules 103 b. However, multiple storage devices 107 may be utilized aswell as different types of storage devices 107.

In decision step 214, depletion of storage device may take place mainlyduring start mode in step 210 of power system 100 i. At start mode instep 210, storage devices 107 may supply load 109 with DC power. Beingin or entering into start mode in step 210 may be indicative of dusk,dawn or excessive shading of PV generators of power system 100. Supplyof DC power to load 109 from storage devices 107, when the amount ofpower from power sources 101 is below a minimum threshold level ofpower, may be such that a first storage device 107 having the mostcharge remains charged while a second storage device 107 having lesscharge is designated to be depleted. In general, for any storage device107 with less charge than another storage device 107 designated fordepletion and subsequent charging cycle may be done to mitigate damageto storage devices for example. The option may remain in decision step214 however, to deplete either the first storage device 107 or thesecond storage device 107 with the condition that at least one storagedevice 107 is left mostly charged at any point in time.

When transitioning out of start mode at step 210, the amount of powerfrom power sources 101 (measured in step 200) may be above a minimumthreshold level of power. State of charge (SOC) of storage devices 107may be measured in step 204 with sensor unit 125. Second storage device107 designated for depletion in decision step 214 along with the powerfrom power sources 101 may be utilized to supply a supplemental power toload 109 (step 216). The supplemental power provided to load 109 fromsecond storage device 107 may extend the provision of power to load 109when power from power sources 101 is insufficient to fully supply load109 (e.g., at dusk or dawn).

Depletion of second storage device 107 may allow in decision step 218for charge of second storage device 107 (step 220) later in the daytimeat a more opportune time when the power from power sources 101 may havean increased power output. The opportune time when power from powersources 101 have an increased power output may also coincide with thesupply of power to load 109 in step 222. The increased power may thenalso be used to charge second storage device 107 rather than the firststorage device 107.

Reference is now made to FIG. 4A, which shows a block diagram 450,according to one or more illustrative embodiments. Power modules103/103P/103 a/103 b may connect to power sources 101, storage devices107, loads 109 and central controller 185 as previously discussed above.Power modules 103/103P/103 a/103 b according to previous descriptionsmay also take into consideration a number of possible options availablefor power modules 103/103P/103 a/103 b and their control by centralcontroller 185. With respect to the control of power modules103/103P/103 a/103 b, signals 452, 454, 456 and 458 may be sent bycentral controller 185 to shut down, to reduce present level of poweroutput, to maintain present level of power output and to increasepresent level of power output respectively of power modules 103/103P/103a/103 b. Three potential supplies of power are shown as P1, P2 and P3.The direction of conversion by power modules 103/103P/103 a/103 b ofpower from power sources 101 and direction of supply of powers P1, P2and P3 are indicated by dashed lines with arrows. Power modules103/103P/103 a/103 b under the control of central controller 185 mayprovide power P1 to loads 109 and/or power P2 to storage devices 107 orstorage devices 107 may provide power P3 to loads 109. At any point intime a potential amount of power Pap may be given by the following:

Pap=P1+P2+P3+Pshed

Where the power Pshed is the amount of power currently being shed owingto control of voltage and/or current to loads 109 and storage devices107, which may not necessarily utilize the feature of increasing powerfrom power sources 101 to loads 109 and/or storage devices 107 viasignal 458, but rather to utilize MPPT circuits 138 in power modules103/103P/103 a/103 b to operate via signal 454 at a point in order toshed some of the power produced by power sources 101.

The description which follows is with reference to FIG. 4B, which is aflow chart describing a method 401 for block diagram 450, according toone or more illustrative embodiments. By way of non-limiting examplepower systems 100, 100 a-100 i previously discussed in a context ofphotovoltaic systems where power sources 101 are photovoltaic panels.The context may include four modes of operation: 1. daytime operation,2. dusk operation, 3. dawn operation 4. And nighttime operation. In thedescriptions that follow, supply and control of powers P1, P2 and P3based on certain priorities may be performed by central controller 185via signals 452, 454, 456 and 458 selected and sent to power modules103/103P/103 a/103 b.

1. Daytime Operation:

During daytime operation, it may be assumed in general that sufficientsunlight is available to generate power from power sources 101. In step400/200, power of power sources 101 and/or power at the terminals ofpower modules 103/103P/103 a/103 b may be measured and conveyed tocentral controller 185 via sensor units 125, 125 a, 125 b and 125 c.Similarly, in step 402/204 the state of charge (SOC) of storage devices107 may also be measured via sensor units 125, 125 a, 125 b and 125 c.

If in decision step 404/202 sufficient generated power is available frompower sources 101, power P1 may be provided to loads 109 in step 408.Power P2 may be supplied to storage devices 107 (step 410) if indecision step 406 the state of charge (SOC) of storage devices 107 islow. If the state of charge (SOC) of storage devices 107 in decisionstep 406 is high, power P1 may be provided to loads 109 in step 408.

Decision step 404/202 may further be explained in terms of how powers P1and P2 may be supplied and controlled to respective loads 109 andstorage devices 107 in the descriptions that follow.

With respect to power P2; power supplied to each storage device 107(step 410) may be based on priorities assigned to each storage device107. Power P2 may be converted power of power sources 101 via powermodules power modules 103/103P/103 a/103 b. Fixed, changeable andupdateable priorities may be assigned to each storage device 107. Forexample, a fixed priority may be when a storage device 107 in a group ofstorage devices 107 may be designated as an emergency storage device 107for a particular load 109 such that the control of charge and dischargeof the emergency storage always takes precedence over other storagedevices 107.

Priorities assigned to each storage device 107 may be further based onthe current state of charge (SOC) of a storage device 107, such thatstorage devices 107 are not damaged by overcharging or from overdepletion: for example, damage to storage devices 107 (batteries) may beavoided for example with reference to FIGS. 2A and 2B; when a battery isnot charged if its SOC is substantially around percentage charge H %, orcharging when the SOC 212 of the battery is in the vicinity belowpercentage charge L % as opposed to charging when the SOC is somewherein between percentage charge H % and percentage charge L %.

Priorities assigned to each storage device 107 may further based on therequired charging parameter such as the control and use of power modules103 b as shown in FIG. 3B to provide constant voltage or current for acertain time period at a particular voltage or current to charge abattery for example. As such different battery types, or differentstorage devices 107 may be accommodated and controlled by centralcontroller 185 via use of signals 452, 454, 456 and 458.

Priorities assigned to each storage device 107 may further based on thepossible requirement to discharge a particular storage device 107 beforecharging in order to avoid damage to a battery and/or where thedischarge of a particular storage device 107 before charging may providethe benefit of supplementing power P1 to loads 109 via power modules 103b when power P1 is not sufficient, for example.

Priorities assigned to each storage device 107 may further based onanticipated night time demand in order to supply power P3 to loads 109,where the bi-directional control of power module 103 b for example isutilized to provide power P3 to load 109 and/or power modules 103 aattached to loads 109.

Priorities assigned to each storage device 107 may further based oncurrent weather conditions which may include information such astemperature or the amount of daylight time remaining. As such, centralcontroller 185, may decide which storage devices 107 in a group ofstorage devices to charge or discharge, for example.

Priorities assigned to each storage device 107 may further based on ifany undue shedding of power (Pshed) is presently going on with respectto power supply of power P1 to loads 109 (step 408) which may bediverted and/or added to the supply of P2 to storage devices 107.

With respect to power P1, power supplied to loads 109 (step 408) may bebased on priorities assigned to each load 109. Power P1 may be convertedpower of power sources 101 via power modules power modules 103/103P/103a/103 b. Fixed, changeable and updateable priorities assigned to eachload 109 may be based on, for example, an updatable load demand historyof the power system with reference to daily or nightly demand, weekdaydemand and monthly demand. The load demand history may be compared withthe present load demand such that more loads 109 may be supplied bypower P1 and/or more power P2 may be utilized in charging storagedevices 107. Alternatively, if the current load demand is higher, powerto loads 109 may be supplemented by P3 by the discharge of some ofstorage devices 107. The load demand history may further take intoconsideration current weather conditions, temperature or the amount ofdaylight time remaining.

With respect to power P1; power supplied to which loads 109 may be basedalso on if there is any undue charging of storage devices 107 that maybe presently going on with respect to possible insufficient supply ofpower P1 to loads 109 (step 408). In that case, the power undulysupplied to storage devices 107 may be diverted and/or added to thesupply of P1 to loads 109. Power supplied to which loads 109 may befurther based on the possible requirement to discharge a particularstorage device 107 into a load 109 before charging the particularstorage device 107.

With regard supply and control of powers P1 and P2 to respective loads109 and storage devices 107, referring back again to FIG. 1D, powermodule 103P may have a number of positive outputs from a single positiveoutput of power circuit 135. The number of positive outputs may providethe option to select via switch SW2 when OFF to provide power to load109 or with switch SW2 when ON to provide power to load 109 and storagedevice 107 for example. More switches may be utilized with the singlepositive output of power circuit 135 to provide multiple outputs tomultiple respective loads 109 and/or storage devices 107. The multipleoutputs may be selected based on the priorities stated above so that aparticular load 109 and/or storage device 107 may receive theappropriate supply of respective powers P1 and P2 under control ofcentral controller 185 which may include the appropriate signals 452,454, 456 and 458 to power modules 103/103P/103 a/103 b. With respect tothe receipt of the appropriate supply of respective powers P1 and P2,power circuit 135 may further include multiple power circuits 135 eachsharing a common input from power source 101 and to provide multiplevoltage level outputs and/or current level outputs in accordance withdifferent voltage and current demands of loads 109 and/or storagedevices 107. The multiple voltage level outputs and/or current leveloutputs may also be selected by respective multiple switches. Theselection by multiple switches may allow a particular load 109/storagedevice 107 in a group of loads 109/storage devices 107 to receive powersupply P1 and/or P2 from the control of power modules 103/103P/103 a/103b via signals 452, 454, 456 and 458 in order to provide a specificvoltage and/or current demand for example.

In some embodiments, control of powers P1 and P2 and supply of power P1and P2 to respective loads 109 and storage devices 107 may be controlledby power line communication via encoded signals to power modules103/103P/103 a/103 b. The encoded signals to power modules 103/103P/103a/103 b may be an instruction to be either ON or OFF in terms of a powermodule either converting or not converting power from the power moduleinput to the power module output. The instruction to be either ON or OFFsent to various power modules 103/103P/103 a/103 b may be so that aparticular load 109 and/or storage device 107 may receive an appropriatesupply of respective powers P1 and P2 under control of centralcontroller 185 that may also include the appropriate signals 452, 454,456 and 458 to power modules 103/103P/103 a/103 b.

2. Dusk Operation and/or 3. Dawn Operation.

If in decision step 404/202 sufficient generated power is not availablefrom power sources 101 when PV panels are heavily shaded in daytime modeor it is dusk or dawn and the SOC of storage devices 107 is also low indecision step 412, a danger alert may be issued in step 416. Supply ofpower to a priority load which is designated as an emergency load may besupplied from a storage device 107 which is designated as an emergencystorage device 107 also in step 416. Otherwise in decision step 412powers P1 and P3 may be supplied to loads 109 (step 414) according totheir priority as discussed above.

4. Nighttime Operation

In nighttime operation, power might not be generated if power sources101 are PV panels. In some embodiments, power sources 101 may instead beDC supplied from a wind turbine or possibly a petrol generator and/oradditionally include PV panels. If the SOC of storage devices 107 isalso low in decision step 412, a danger alert may be issued in step 416.Supply of power to a priority load that is designated as an emergencyload may be supplied from a storage device 107 that is designated as anemergency storage device 107 at step 416. Otherwise, at decision step412 powers P1 (from the wind turbine or the petrol generator) and P3from storage devices 107 may be supplied to loads 109 (step 414)according to their priority as discussed above. If power sources 101 arePV panels, then P3 from storage devices 107 may be supplied to loads 109in step 414 according to their priority as discussed above.

Reference is made to FIG. 5 , which shows a graphical user interface(GUI) 550, according to one or more illustrative embodiments. Areas 50,51, 52, 53, 54 and 55 may be included on one graphical screen or bedisplayed on different graphical screens (e.g. depending on the screensize available). In the description that follows, a touch screen isreferenced by way of example, but other screens such as computermonitors, laptop screens or smart phone screens may be used where itemsmay be selected for example by mouse and/or pointer.

GUI 550 may include a text area 50 which may give a user information asto the location of power system 100, 100 a-100 i for example, the localtime and date, an indication as to the weather conditions at thelocation, temperature at the location and the wind speed at the locationof a power system 100, 100 a-100 i. Text area 50 may also serve overallas an icon that when touched or swiped by the user using a touch screendevice such as a smart phone, allows a sub menu to appear. The sub menumay, for example, allow the user to view another DC power stationlocated elsewhere to be monitored by the user.

GUI 550 may include a stage of charge (SOC) area 51 that shows thepercentage (%) SOC of three storage devices 107 which may be used inpower systems 100, 100 a-100 i. The percentage (%) SOC of the threestorage devices 107 is shown by respective cross hatchings. Each of thepercentage (%) SOC of the three storage devices 107 displayed may alsoserve overall as separate icons which when touched or swiped by the userallows shows a further detail about a particular storage device 107.Using the example of a battery for storage device 107, the furtherdetails may include information of battery type, rating in terms ofvoltage, current and ampere hours (Ah), location of the battery, thenumber of times the battery has been charged/discharged, the projectedbattery life of a battery based on its usage. The further details mayalso provide a remote means for a configuration and a control of thethree storage devices 107 via respective power modules 103 b forexample. The configuration may include the option to disconnect and/ornot use a particular battery, the option to designate a battery to havegreater priority over the other batteries to be charged first forexample, to schedule a battery for replacement based on its currentusage, the option to change parameters of a charge profile for a batteryor to allow an upload and/or update of a charge profile for a battery.

GUI 550 may include a load utilization area 52 that shows four loads 109and indicates to a user of the amount of power, voltage and current aload 109 is presently consuming. Each of the four loads 109 displayedmay also serve overall as separate icons which when touched or swiped bythe user allows shows a further detail about a particular load 109. Thedetail about a load 109 may include, for example, a load profile for aparticular load 109. The load profile may also include updatedinformation with regards to an updatable load demand history of thepower system with reference to daily and nightly demand, weekday demandand monthly demand. The load profile may be updated and/or beconfigurable via load utilization area 52 in order control powerdelivery to loads 109. Options may be provided to possibly disconnectload 109 or to change the voltage and/or currents supplied to load 109by providing access and control of power modules 103 a that may beattached to respective loads 109.

GUI 550 may further include DC generation area 53, which shows fivepower outputs from power sources 101 connected to power modules103P/103. If the outputs of power modules 103P/103 are connected inseries to form a string as described in FIGS. 3A and 3B for example,then the voltage of the string (Vstring) may be displayed also in DCgeneration area 53. Each of the five powers displayed may also serveoverall as separate icons that, when touched or swiped by the user,shows a further detail about a particular power source 101 andrespective power modules 103P/103. The further detail for example mayinclude the voltages and currents sensed by sensor unit 125, so as toindicate the voltages and currents on respective inputs and outputs ofpower modules 103P/103, for example. Based on the further details, auser may be given the option to remotely switch off or perhaps bypass aparticular power module 103P/103 output. Related to DC generation area53 is power utilization area 54 which indicates the total power (Pgen)currently being generated and the amount of power currently being shed(Pshed). Power may be shed since loads 109 and storage devices 107 maynot need so much of the power currently being produced.

GUI 550 may further include a graphical display area 55 to displayuseful graphs to the user. A graph is shown of power usage versus thetime of day. The anticipated power consumption 500 is displayed as asolid line and the actual real time or near real time power consumption502 is displayed as a dotted line. Graphical display area 55 may alsoserve overall as an icon which, when touched or swiped by the user,allows the user to select from different sub menus different graphicaldisplays of different parameters of a power system or the topographicallayout of power sources 101 in the power system for example. The remoteconfigurations described for GUI 550 which include in particular thesupply and control of powers P1 to loads 109 and P2 storage device 107and/or power P3 from storage device 107 to loads 109 may be provideddynamically via GUI 550 rather than as the result of something that isstatically predefined. The supply and control of powers P1 to loads 109and P2 storage device 107 and/or power P3 from storage device 107 toloads 109 may be provided dynamically and/or statically predefined,according to the priorities described in further detail with respect toFIGS. 4A and 4B.

According to some illustrative embodiments, a power source with directcurrent (DC) output terminals is connected to the input terminals of aDC power module, in which the DC power module includes first and secondpositive DC output terminals respectively connected to positive DC inputterminals of a load and a storage device. The first and second positiveDC outputs of the power module may be utilized so that power from DCpower module may be supplied to the load only, or to the load and to thestorage device.

According to some illustrative embodiments, a switch is provided betweenan output of a power source and an input of a DC power module, in whichthe switch receives a signal to disconnect the output of the powersource from the input of the DC power module when an unsafe condition isdetected. The unsafe condition may be detected by one or more sensorsthat are capable of sensing parameters such as power, current, voltage,and temperature at respective locations of a DC power generation systemthat includes the power source and the DC power module.

According to some illustrative embodiments, DC power sources areconnected to a load and/or a storage device via multiple power modules.The power modules may control power such that the load and/or thestorage device may match the DC power from the DC power sources, inwhich power may be shed from the load and/or the storage device.Optionally, DC power from the storage device may be matched and suppliedto the load, or optionally DC power from the DC power sources may bematched and supplied to the load. To control power, the power modulesmay include sensors capable of sensing parameters such as powers,currents, voltages, coulombs, and temperatures of their respectiveinputs and outputs.

According to some illustrative embodiments, the state of charge of astorage device may be sensed. Upon the sensed charge of the storagedevice being above a first predetermined level of state of charge, thepower stored in the storage device may be supplied to a load, wherebythe stored charge of the storage device is discharged to the load. Uponthe sensed charge of the storage device being below a secondpredetermined level of state of charge, the storage device may then becharged and power to the load may be supplied responsive to the measuredpower.

According to some illustrative embodiments, a power circuit may beconnected at its output to a load and to a storage device. A switch maybe provided at an output terminal of the power circuit, to enableconnection or disconnection between the output terminal of the powercircuit and an input terminal of the storage device. With the switch inan ON position, the load and the storage device are connected inparallel across an output terminal of the power circuit. With the switchin an OFF position, the load remains connected across the outputterminal of the power circuit, and the storage device is disconnectedfrom the output terminal of the power circuit. In the context of aphotovoltaic (PV) panel implementation of a power system, operation ofthe switch in the ON position may allow power to be supplied to the loadand to the storage device when power from a power source (e.g., solarpanel) providing power to the power circuit is sufficient (e.g., duringthe daytime). Operation of the switch in an OFF position may allow powerto be supplied to the load if charging of the storage device is to beavoided, such as when the storage device is already substantially fullycharged, or to reduce the number of charging cycles of the storagedevice, or when power from the power source supplying power to the powercircuit is insufficient to both power the load and the charge thestorage device. When power from the power source is insufficient (e.g.,during the nighttime), the switch may be placed in the ON position,allowing power from the storage device to be applied to the load.

According to some illustrative embodiments, a direct current (DC) systemmay be utilized to supply DC power to a load and/or a storage device.The DC system may include various interconnections of groups of DC powersources that also may be connected in various series, parallel, seriesparallel and parallel series combinations for example.

According to some illustrative embodiments, the groups of DC powersources may include groups of DC power sources where the direct currentto supply a load and/or a storage device may be derived from renewableenergy sources such as sunlight, wind, rain, tides, waves, andgeothermal heat. Devices that convert these renewable energy sourcesinclude for example photovoltaic solar generators, wind generators andwind turbines. The groups of DC power sources may also include groups ofDC power sources where the direct current is derived from non-renewableenergy sources. Devices that convert these non-renewable energy sourcesinto DC power to supply a load and/or a storage device may includepetrol, oil and gas generators and/or turbines for example. The directcurrent may also be derived from rectified or converted sources ofalternating current provided from a switched mode power supply, dynamoor alternator for example.

According to some illustrative embodiments, DC power sources in a DCpower system are interconnected to various groups of DC sources. Eachgroup of DC sources may contain different types of DC power derived fromboth renewable and non-renewable energy sources, so that the DC powergenerated may be configured to meet the criteria of providing anuninterruptable source of DC power to a load from the DC power sourcesand/or to store some of the DC power in a storage device. A part of thecriteria may be to utilize energy previously stored in the storagedevice to subsequently supply power and what might be considered to beemergency power to the load when the DC sources are not able to producepower owing to lack of sunlight, wind and/or fuel for example.

According to some illustrative embodiments, DC power sources may includea connection of DC sources to a load and/or storage device via multiplepower modules. The power modules may control power such that the loadand/or storage may match the DC power from the DC power sources, powermay be shed from the load and/or storage, optionally DC power fromstorage device may be matched and supplied to the load or optionally DCpower from the DC power sources may be matched and supplied to the load.To control power, the power modules may include the capability ofsensing parameters such as powers, currents, voltages, coulombs,temperatures of their respective inputs and outputs via sensors to acontroller.

According to some illustrative embodiments, the power modules maycontrol power to the load and/or storage device according to a loadprofile. The load profile may include an information update viacommunication interfaces included in the power modules that communicatewith each other to receive weather information such as present andforecasted temperature, wind speed, cloud cover and amount of sunlightfor example. The load profile may also include updated information withregards to an updatable load demand history of the power system withreference to daily and nightly demand, weekday demand and monthlydemand. The updatable load demand history of the power system may alsotake into account the amount of fuel and cost of fuel available toutilize petrol, oil and gas generators and/or turbines instead ofutilizing other types of DC power provision for example.

According to some illustrative embodiments, the power modules maycontrol power to the load and/or storage device according to a chargeprofile of a storage device. Using the example of a battery for thestorage device, the charge profile may ensure optimal charging of thebattery that may prefer a constant voltage level or constant current forat least a minimum period of time. The charge profile may also specifycontrol of the temperature of the battery during charging which mayimprove the performance and/or reliability of the battery, since thebattery may need to stay cool when being charged so as to ensure optimalcharging.

According to some illustrative embodiments, consideration may be givento different types of batteries when charging and discharging to ensurethat correct voltages, currents, temperatures and appropriate timeperiods of charge and discharge are monitored, controlled and applied tobatteries so as to avoid damage to the batteries. In addition, thecharge profile may include reconfiguration of the charge profile basedon data of the transfer of charge and/or discharge of a battery in orderto access the ageing and use of batteries. Such data logging may then beused to provide an estimate of projected battery life and timing ofbattery maintenance and replacement for example.

According to some illustrative embodiments, the power modules may beconfigurable to control the delivery of power of the DC sources to aload and/or a storage device. The power modules may be configurable tocontrol the delivery of power to a load from energy previously stored inthe storage device. The power modules may be configurable to control thedelivery of power to a load from both the DC power sources and thestorage device together.

According to some illustrative embodiments, a method for a directcurrent (DC) power system that may include a controller, multiple DCpower sources, multiple DC power modules, multiple bi-directional powermodules and multiple storage devices. In the method, each of the powersources may be coupled to a respective DC power module. The powermodules outputs may be coupled in a connection that may be a seriesconnection of the power modules outputs, to form thereby, a serialstring of power module outputs. The connection may also be a parallelconnection of the power modules outputs. The serial string or theparallel connection may be coupled to a load and may be also coupled tothe bi-directional power modules. Each of the bi-directional powermodules may be coupled to respective storage devices. Power of each ofthe power sources may be measured by sensors provided with each of thepower modules.

According to some illustrative embodiments, upon the power beingmeasured, a signal may be transmitted to the power module and/or thebi-directional power modules. The signal sent to power modules may servethe function of instructing the power modules to shut down completely(e.g., using an explicit message) due, for example, to a safetycondition in the power system, to reduce power (e.g., an explicitmessage or lack of a signal) in order to shed power, to let the powermodules to continue to control power at the present level or to increasepower to a load and/or storage device. In general, the supply of powerto the load and/or storage device may be controlled responsive to thepower measured. The load may comprise multiple loads, and multiple DCpower modules may be respectively coupled between the serial string andthe loads so that loads with different voltage levels and currentrequirements may be accommodated. Similarly, different types of storagedevices may also include respective bi-direction power modules so as toaccommodate the different voltage levels and current level requirementssuch as constant voltage or constant current for charging the storagedevice for example. The bi-directional nature of the power modules ofrespective storage devices also allow the accommodation and provision ofthe different voltage levels and current level requirements of themultiple loads, when power to the loads is provided from the storagedevices.

According to some illustrative embodiments, the control of powersupplied to the load may further include at least one of the storagedevices to be depleted prior to subsequent charging of the at least onestorage device, thereby mitigating damage to the at least one storagedevice. The at least one storage device depleted may additionally demandthat at least one of the other the storage devices remains substantiallycharged so that it may be used in an emergency situation for example orto satisfy a requirement that a minimal amount energy is alwaysavailable to be supplied.

According to some illustrative embodiments, with respect to the controlof power supplied to the load, the state of charge of the storagedevices may be sensed. Upon the sensed charge of the storage devicesbeing above a second predetermined level of state of charge, the powerfrom the storage devices may be supplied to the load, thereby the storedcharges of the storage devices are discharged to the load. Upon thesensed charge of the storage devices being below the secondpredetermined level of state of charge and the power measured beingabove the predetermined level, the storage devices may then be chargedand power to the load may be supplied responsive to the measured power.

According to some illustrative embodiments, the discharge of the storagedevices may leave one of the storage devices substantially fully chargedand the charge of the storage devices may be performed on the storagedevices t have been discharged to a previously defined state of minimalcharge.

According to some illustrative embodiments, a DC power system mayinclude a power source with a first output terminal, and a power modulehaving a first input terminal and a second output terminal. The firstinput terminal of the power module may be connected to the first outputterminal of the power source. The DC power system may further include astorage device having a second input terminal connected to the secondoutput terminal of the power module, and a load having a third inputterminal connected to the second output terminal of the power module.

According to some illustrative embodiments, the power module may furtherinclude a controller operatively connected to a memory. A sensor unitmay be operatively connected to the controller and the controller may beconfigured to sense an electrical parameter on the first input terminal,the second output terminal, the second input terminal or the thirdterminal. A power circuit may be configured to provide and control apower on the second output terminal of the power module responsive tothe sensed electrical parameter.

According to some illustrative embodiments, the DC power system maystill further include a second power module having a fourth inputterminal and a third output terminal. The fourth input terminal may beconnected between the second output terminal of the power module and thethird input terminal of the load. The DC power system may also include athird power module having a fifth input terminal and a fourth outputterminal. The fifth input terminal of the third power module may beconnected between the second output terminal and the second inputterminal of the storage device. The third power module may be configuredto convert power from the fifth input to the second input terminal ofthe storage device or to convert power from the second input terminal ofthe storage device to the second output terminal.

According to some illustrative embodiments, the DC power system mayfurther include a switch disposed between the second output terminal andthe first input terminal of the power module. The switch may be operatedresponsive to the electrical parameter sensed and the state of charge ofthe storage device. A second switch may be disposed between the firstoutput terminal of the power source and the first input terminal of thepower module.

According to some illustrative embodiments, a central controller may beoperatively connected to the power module. The power circuit may beconfigured by the central controller to provide and control a power onthe second output terminal of the power module responsive to the sensedelectrical parameter. The electrical parameter sensed may be voltage,current, resistance, coulombs and power. The power circuit may be a buckcircuit, a boost circuit, a buck/boost circuit or a buck+boost circuit.All optional and preferred features and modifications of the describedembodiments and dependent claims are usable in all aspects of theinvention taught herein. Furthermore, the individual features of thedependent claims, as well as all optional and preferred features andmodifications of the described embodiments are combinable andinterchangeable with one another.

It is noted that various connections are set forth between elementsherein. These connections are described in general and, unless specifiedotherwise, may be direct or indirect; this specification is not intendedto be limiting in this respect. Further, although elements herein aredescribed in terms of either hardware or software, they may beimplemented in either hardware and/or software. Additionally, elementsof one embodiment may be combined with elements from other embodimentsin appropriate combinations or sub-combinations. For example, theswitch(s), sensor(s), power source(s), storage element(s), andinterconnections of one embodiment may be combined with similar elementsof another embodiment and used in any combination or sub-combination.Also, for example, power module 103P shown in FIGS. 1A, 1F, 1G, 1H, 1J,3A and 3B may be replaced by power module 103 that has a single positiveoutput. Storage device 107 shown in FIG. 3A may also connected to apower module 103 b as shown in FIG. 3B. Power sources 101 shown in theFigures may be alternating current (AC) sources and power modules 103and 103P connected thereto may serve as AC-to-DC converters such asrectifiers and/or switched mode power supply, for example. One skilledin the art will recognize that the various embodiments detailed abovemay be combined in suitable combinations and that portions of theembodiments may be unitized in various sub-combinations.

1. A system, comprising: a plurality of power sources; a string of powerconverters connected to the plurality of power sources; and acontroller, wherein the controller is configured to send, to one or morepower converters of the string of power converters and based on adetermination that a direct current (DC) power will satisfy arequirement of at least one DC load, instructions to output the DCpower, and wherein each power converter of the string of powerconverters is configured to: receive the instructions from thecontroller; and output, based on the instructions, the DC power.
 2. Thesystem of claim 1, wherein one or more outputs, of the string of powerconverters, are connected in serial.
 3. The system of claim 1, whereinone or more outputs, of the string of power converters, are connected inparallel.
 4. The system of claim 1, wherein the controller is configuredto determine the DC power based on: a first power available at theplurality of power sources; and a second power being supplied to the atleast one DC load before sending the instructions.
 5. The system ofclaim 1, further comprising: at least one energy storage deviceconnected to the string of power converters.
 6. The system of claim 5,wherein the controller is further configured to: monitor a state ofcharge (SOC) of the at least one energy storage device; and cause, basedon the SOC, output of a stored power of the at least one energy storagedevice.
 7. The system of claim 5, wherein the controller is furtherconfigured to: monitor a SOC of the at least one energy storage device;and cause, based on the SOC being below a first threshold and the DCpower being above a second threshold, transfer of the DC power to boththe at least one DC load and the at least one energy storage device. 8.The system of claim 5, wherein the controller is further configured to:monitor a SOC of the at least one energy storage device; and cause,based on the SOC being above a first threshold and the DC power beingbelow a second threshold, transfer of a stored power from the at leastone energy storage device to the at least one DC load.
 9. The system ofclaim 5, wherein the controller is further configured to: monitor a SOCof the at least one energy storage device; and cause, based on the SOCbeing above a first threshold and the DC power being above a secondthreshold, transfer of the DC power to the at least one DC load.
 10. Thesystem of claim 5, wherein the controller is further configured to:monitor a SOC of the at least one energy storage device; and disable,based on the SOC being below a first threshold and the DC power beingbelow a second threshold, transfer of the DC power to the at least oneenergy storage device and to the at least one DC load.
 11. The system ofclaim 1, wherein the instructions comprise instructions to: set a DCvoltage corresponding to the DC power, increase power, reduce power,keep alive, maintain present power, or shut down.
 12. The system ofclaim 1, wherein the requirement comprises a voltage requirement or acurrent requirement.
 13. The system of claim 1, wherein a power sourceof the plurality of power sources comprises at least one photovoltaicpanel, and wherein a power converter, of the string of power converters,is connected to the at least one photovoltaic panel and comprises aMaximum Power Point Tracking (MPPT) circuit.
 14. The system of claim 13,wherein the power converter comprises a DC to DC buck+boost converter.15. The system of claim 1, wherein a power source of the plurality ofpower sources comprises an alternating current (AC) power source, andwherein a power converter, of the string of power converters, isconnected to the AC power source and comprises an AC to DC converter.16. The system of claim 1, further comprising: at least one DC to ACpower converter, wherein an input of the at least one DC to AC powerconverter is connected to the string of power converters, and wherein anoutput of the at least one DC to AC power converter is connected to anAC load.
 17. A method, comprising: receiving, by each of a plurality ofpower converters and by using Maximum Power Point Tracking (MPPT), adirect current (DC) input power from a different power source of aplurality of power sources; determining, by a controller, that a DCoutput power will satisfy a requirement of at least one DC load;sending, by the controller, to the plurality of power converters andbased on the determining, instructions to output the DC output power;and outputting, by each of the plurality of power converters and basedon the instructions, the DC output power.
 18. The method of claim 17,wherein a power source of the plurality of power sources comprises atleast one photovoltaic panel.
 19. The method of claim 17, wherein apower source of the plurality of power sources comprises an alternatingcurrent (AC) power source, and wherein a power converter, of theplurality of power converters, connected to the AC power sourcecomprises an AC to DC converter.
 20. The method of claim 17, furthercomprising: converting, by at least one DC to AC power converter, the DCoutput power to an AC power using; and outputting, by the at least oneDC to AC power converter, the AC power to an AC load.
 21. The method ofclaim 17, comprising: monitoring, by the controller, a state of charge(SOC) of at least one energy storage device connected to the string ofpower converters; and causing, by the controller and based on the SOCand the DC power, transfer of a stored power from the at least oneenergy storage device to the at least one DC load.